Ultra-low frequency high voltage generatorand DC high voltage generator are both high voltage generators, whose function is to detect hidden defects in the insulation of electrical equipment, so as to understand and grasp the insulation state of equipment and ensure the safe and reliable operation of high-voltage electrical equipment. However, they are worlds apart in performance.
Ultra-low frequency high voltage generatoris suitable for withstand voltage tests of electrical equipment with large equivalent insulation capacitance, such as power cables, power capacitors, medium-sized generators and motors, etc.
The ultra-low frequency insulation withstand voltage test is actually an alternative to the power frequency withstand voltage test. Because when using the power frequency withstand voltage method to test large-capacity equipment, a test transformer or resonant transformer with large capacity is required. This makes it very inconvenient to use. In order to solve this contradiction, the power department adopted reducing the test frequency and reducing the capacity of the test power supply. From years of theory and practice at home and abroad, it has been proved that using 0.1Hz ultra-low frequency withstand voltage test to replace the power frequency withstand voltage test not only has the same equivalence, but also greatly reduces the volume and weight of the equipment. Theoretically, the capacity is about one five-hundredth of the power frequency, and it has more advantages than the power frequency test.
DC high voltage generator is a common DC withstand voltage device in power preventive test equipment. It generally uses power frequency high voltage rectified by high-voltage silicon stack to obtain DC high voltage. This method has long been abandoned due to large equipment size, poor stability, and high ripple coefficient. Now it is only found in a few laboratories with self-made, low precision requirements, and some X-ray machines for safety inspection.
Early DC high voltage generators could be used for DC withstand voltage tests of power cables to check the insulation performance of cables. However, with the research of power preventive tests, it was found that checking cable insulation performance under DC conditions is not perfect and causes greater hidden damage to cables. Gradually, the scope of use of DC high voltage generators has been limited to a certain extent. At present, DC high voltage generators are mainly used to measure the leakage current of zinc oxide arresters or to serve as DC power supplies.
Ultra-low frequency high voltage generatorand DC high voltage generator are similar in design principle, including the control part, high voltage generation part, and voltage divider measurement part. From the technical parameters, the biggest difference between the two is that one produces DC high voltage; the other produces high voltage with a frequency of 0.1Hz, which is approximately DC.
.